This invention relates to apparatus for cushioning the motion of a reciprocating machine part and finds particular utility in cushioning the air-operated working piston of a neck ring invert mechanism or take-out mechanism of a Hartford individual section (I. S.) type glassware forming machine.
The typical Hartford I. S. glassware forming machine comprises six, eight or 10 individual sections arranged together in side-by-side relationship. Each section comprises a self-contained unit which includes a blank (or parison) mold station and a blow mold station. Molten glass gobs are delivered by means of a gob distribution system, as shown for example in U.S. Pat. No. 3,721,544, in a predetermined sequence to the upwardly open blank molds of each section. The gob of molten glass is formed into a parison at the blank station, and then transferred to the blow station by a neck ring invert mechanism which includes a neck mold. The neck mold mates with the blank mold at the blank station and also supports the parison during its inversion and transfer to the blow station. At the blow station the blow mold is closed around the parison and supports the parison just below its finish, allowing the neck ring to be opened, and the neck ring invert mechanism then reverts the neck ring mold to the blank station. Air is delivered to the interior of the parison and the ware is formed in the blow mold into its final shape. After the air is shut off, the blow mold opens and tongs move into the blow station, close around the newly formed ware, and the article is taken out of the blow station by a take-out mechanism and transferred to the deadplate portion of a take-away conveyor system. A good description of the Hartford type I. S. machine can be seen in U.S. Pat. No. 1,911,119, and a typical neck ring invert mechanism is shown in FIGS. 4 and 5 of that patent.
Attempts have been made to cushion the reciprocating member of the neck ring invert mechanism and the reciprocating member of the take-out mechanism, but the means utilized for this purpose have not been entirely satisfactory. Pneumatic cushioners are known, for example, for cushioning neck ring invert mechanisms and glass cutting shears; see U.S. Pat. No. 2,518,871, for example. However, pneumatic cushioners have the disadvantage that when the mechanism to be cushioned is located in an inaccessible place, such as the inside of a section box of an I. S. glassware forming machine, it is extremely difficult to adjust the position at which the pneumatic cushion becomes operative. This is so because the air line through which the air cushioning the piston is allowed to bleed to atmosphere (through an adjustable orifice which regulates the cushioning) must be long in order to place the adjustable orifice in a position accessible to the machine operator. The length of the air line causes a large drop in the pressure of the air passing therethrough with the result that the adjusting means has no sensitivity in controlling the cushioning. The inaccessible locations of the neck ring invert mechanism and the take-out mechanism of an I. S. glassware forming machine make the use of pneumatic cushioner undesirable.
My invention overcomes the problems inherent in a pneumatic cushioning system and allows adjustment of a hydraulic cushioning means used to cushion mechanisms which are relatively inaccessible.